JP2010202804A - Method for crosslinking adhesion of fluororubber and crosslinked fluororubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for crosslinking adhesion of a fluororubber to keep firm adhesive force between the fluororubber and a metal even after exposure to steam, and a crosslinked fluororubber bonded to the metal and obtained by the method. <P>SOLUTION: The method for crosslinking adhesion of a fluororubber to a metal substrate includes coating of the substrate with at least one of solutions of materials selected from the group consisting of silane coupling agents and hydrolyzed products and partially condensed products of the silane coupling agent, drying of the solution, baking of the substrate at 200-300°C and crosslinking adhesion of the fluororubber composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for cross-linking and bonding fluororubber to a metal substrate and a cross-linked fluororubber.

Fluoro rubber can be used in an environment where general-purpose rubber materials have poor durability and cannot be applied, taking advantage of its excellent steam resistance, water resistance, plasma resistance, heat resistance, chemical resistance, etc. Used as seals, hoses, vibration-proof members, tubes, belts, etc. In these applications, fluororubber is often used by being bonded to a metal substrate.
Conventionally, adhesion between a fluororubber containing a peroxide compound as a vulcanizing agent and a metal substrate is performed using an adhesive such as a silane coupling agent or an epoxy. In the case of bonding with a silane coupling agent, the silane coupling agent-containing adhesive is applied to the surface of the metal substrate before the fluororubber is bonded to the metal substrate, dried, and then baked.

Common silane coupling agents are often monomers with boiling points and have a vapor pressure, so after applying an adhesive containing a silane coupling agent to a metal substrate, 200 ° C or higher When baking at such a high temperature, the silane coupling agent volatilizes, and there is a concern that a good adhesion effect cannot be exhibited. Then, the baking process which makes baking temperature 80-150 degreeC and about 5 to 30 minutes was performed. However, under these conditions, the fluororubber did not have sufficient adhesion to the metal substrate.

In order to improve the adhesion to a metal substrate, a compositional approach of fluororubber has also been performed. A silane coupling agent-containing adhesive is applied to the surface of the metal substrate, dried and then baked, and then the treated surface is selected from fluororubber, vulcanizing agent and alkylene glycol, glycerin and alkyl cellosolve. There has been proposed a method of adhering fluororubber to a metal substrate by placing a special fluororubber composition containing at least a seed and vulcanizing under pressure (see Patent Document 1). Also in this document, the example describes that the baking temperature after applying the silane coupling agent-containing adhesive on the surface of the metal substrate and drying it is 120 ° C.

However, the method of this document has a problem that the adhesion between the fluororubber and the metal is lowered when exposed to a steam environment. Therefore, pretreatment such as blasting is performed on the metal base, and the fluororubber and the metal base are bonded using physical interaction. However, in such a method, there are problems such as an increase in the number of manufacturing steps and mixing of foreign matters such as metal powder generated in the processing into the fluororubber.
In addition, a method has been proposed in which an adhesive is applied to a metal substrate such as stainless steel and then a fluororubber composition containing a crosslinking agent is crosslinked and bonded (see, for example, Patent Document 2). However, this bonding method has a problem that the adhesive strength is remarkably reduced when used in an environment where excellent steam resistance is required.

Synthetic rubbers other than fluoro rubbers are phenol resin / chlorinated to improve resistance to hot water adhesion between ethylene / propylene rubber (EPDM) and acrylate rubber / ethylene copolymer rubber (AEM) and metal. A method of bonding using a polyethylene-based adhesive has been proposed (see, for example, Patent Document 3). However, even when this phenol resin / chlorinated polyethylene adhesive is applied to the adhesion between the fluororubber and the metal substrate, the adhesion between the fluororubber and the metal substrate is difficult.

Recently, a primer having an epoxy resin-amine curing agent has been proposed as an adhesive in order to improve hot water resistance in adhesion between a fluororubber paint and a metal substrate. In this proposal, the undercoat contains an epoxy resin, and the undercoat is cured at 200 ° C. (see, for example, Patent Document 4). However, the adhesive article between the fluororubber and the metal substrate obtained by this method has insufficient steam resistance.

JP-A 64-54037 JP-A-6-157686 JP 2004-27068 A JP 2008-308509 A

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a cross-linking adhesion method between a fluororubber and a metal substrate excellent in steam resistance and a cross-linking fluororubber obtained by the cross-linking adhesion method. And

The present invention provides a method for cross-linking and bonding fluororubber having the following constitution, and a cross-linked fluororubber obtained by the method.
[1] One or more kinds selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof when the fluororubber composition is crosslinked and bonded to the metal substrate. A method for cross-linking and adhering a fluororubber, comprising: applying a solution containing selenium, drying, baking the substrate at a temperature of 200 to 300 ° C., and cross-linking the fluororubber composition.
[2] The method for cross-linking and adhering fluororubber according to [1], wherein the cross-linking of the fluororubber composition is peroxide cross-linking using an organic peroxide.
[3] The fluororubber crosslinking according to [1] or [2], wherein the silane coupling agent is one or more selected from the group consisting of an amino group-containing silane coupling agent and a vinyl group-containing silane coupling agent. Bonding method.

[4] The fluororubber crosslinking method according to any one of [1] to [3], wherein the firing time is 1 to 120 minutes.
[5] The temperature of the metal substrate when applying a solution containing at least one selected from the group consisting of the silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof is 0 to The cross-linking adhesion method for fluororubber according to any one of [1] to [4], which is 80 ° C. or lower.
[6] A cross-linked fluororubber obtained by the method for cross-linking fluorocarbon rubber according to any one of [1] to [5], wherein the metal base material is subjected to a pressure cooker test held in a steam atmosphere at 135 ° C. for 70 hours. A crosslinked fluororubber characterized in that the ratio of cohesive failure of the fluororubber at the peeling interface between the fluorinated rubber and the crosslinked fluororubber is 80% or more.

  According to the crosslinked adhesion method of the present invention, a crosslinked fluororubber having excellent adhesive force even in a steam environment between the crosslinked fluororubber and the metal substrate can be obtained. That is, the cross-linked fluororubber of the fluororubber and the metal substrate of the present invention retains excellent adhesion even after being exposed to steam. Further, the crosslinked fluororubber obtained by the crosslinking adhesion method of the present invention is excellent in steam resistance, water resistance, plasma resistance, heat resistance, chemical resistance and the like. Therefore, the cross-linked fluororubber of the present invention is applied to fields requiring chemical resistance, steam resistance and heat resistance such as composite parts such as oil seals, particularly engines, pumps, rolls, etc., taking advantage of these characteristics. It is particularly effective as an article.

The fluororubber composition used for cross-linking adhesion of the present invention contains fluororubber and a cross-linking agent.
As fluorine content in fluororubber, 40 mass%-75 mass% are preferable, 45 mass%-75 mass% are more preferable, 50 mass%-75 mass% are the most preferable. Within this range, the fluororubber is excellent in heat resistance, chemical resistance, electrical insulation and steam resistance.

Specific examples of the fluororubber include vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, vinylidene fluoride / chlorotrifluoroethylene copolymer, tetrafluoroethylene / Propylene copolymer, tetrafluoroethylene / propylene / vinylidene fluoride copolymer, tetrafluoroethylene / propylene / vinyl fluoride copolymer, tetrafluoroethylene / propylene / trifluoroethylene copolymer, tetrafluoroethylene / propylene / Pentafluoropropylene copolymer, tetrafluoroethylene / propylene / chlorotrifluoroethylene copolymer, tetrafluoroethylene / propylene / ethylidene norbornene copolymer, hexafluoropropylene copolymer Pyrene / ethylene copolymer, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer, vinylidene fluoride / tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer, and the like.

The fluoro rubber is selected from the group consisting of a tetrafluoroethylene / propylene copolymer, a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, and a tetrafluoroethylene / propylene / vinylidene fluoride copolymer. One or more are preferred.
The copolymer composition of the tetrafluoroethylene / propylene copolymer is preferably 40/60 to 70/30 (molar ratio), more preferably 45/55 to 65/35 (molar ratio), and 50/50 to 60 / 40 (molar ratio) is most preferable.
The copolymer composition of the vinylidene fluoride / hexafluoropropylene copolymer is preferably 60/40 to 95/5 (molar ratio), more preferably 70/30 to 90/10 (molar ratio), and 75/25. ˜85 / 15 (molar ratio) is most preferred.
The copolymer composition of vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer is preferably 50/5/45 to 65/30/5 (molar ratio), and 50/15/35 to 65/25 / 10 (molar ratio) is more preferable, and 50/20/30 to 65/20/15 (molar ratio) is most preferable.

  The copolymer composition of tetrafluoroethylene / perfluoro (alkyl vinyl ether) is preferably 50/50 to 95/5 (molar ratio), more preferably 55/45 to 85/15 (molar ratio), and 60/40 to 80/20 (molar ratio) is most preferred. As perfluoro (alkyl vinyl ether), perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), perfluoro (methoxyethyl ether), perfluoro (methoxyethyl ether), perfluoro (methoxy) Ethyl ether) and perfluoro (propoxyethyl ether). In particular, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), and perfluoro (propyl vinyl ether) are preferable.

Examples of commercially available tetrafluoroethylene / propylene copolymers include “AFLAS150P” (manufactured by Asahi Glass Co., Ltd., tetrafluoroethylene / propylene binary copolymer).
As the fluororubber crosslinking agent used in the present invention, all conventionally known crosslinking agents can be used, but organic peroxides are preferred because the crosslinked rubber is excellent in steam resistance. Any organic peroxide can be used as long as it can easily generate radicals in the presence of heating and a redox system, but those having a half-life of 1 minute are preferably 130 to 220 ° C.

  Specific examples thereof include 1,1-di (t-hexylperoxy) -3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t- Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, α, α'-bis (t-butylperoxy) -p-diisopropylbenzene, 2,5-dimethyl-2,5-di (t-butyl Peroxy) -hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -hexyne-3, dibenzoyl peroxide, t-butylperoxybenzene, 2,5-dimethyl-2 , 5-di (benzoylperoxy) hexane, t-butylperoxymaleic acid, t-hexylperoxyisopropyl monocarbonate and the like. Of these, α, α'-bis (t-butylperoxy) -p-diisopropylbenzene is preferable. The organic peroxide is excellent in peroxide crosslinkability of fluororubber.

The fluororubber composition used in the present invention preferably contains a crosslinking aid.
Examples of the crosslinking aid include triallyl cyanurate, triallyl isocyanurate, triacryl formal, triallyl trimellitate, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalamide, triallyl phosphate and the like. Of these, triallyl isocyanurate is preferable.
In the fluororubber composition, the content of the organic peroxide is 0.1 to 5 parts by mass, preferably about 0.2 to 4 parts by mass, most preferably 0.5 to 3 parts by mass per 100 parts by mass of the fluororubber. Part. Within this range, the crosslinking efficiency of the organic peroxide is high, and the amount of ineffective decomposition can be suppressed.

  The content of the crosslinking aid is preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and most preferably 3.5 to 10 parts by mass with respect to 100 parts by mass of the fluororubber. . If the content is too small, the crosslinking rate is slow and the crosslinking degree is low. If the amount is too large, the elongation of the crosslinked rubber may be low. Within this range, the crosslinking rate is high, the degree of crosslinking of the resulting crosslinked rubber is high, and the crosslinked rubber is excellent in properties.

The fluororubber composition used in the present invention preferably contains carbon black and other additives.
There is no restriction | limiting in particular as carbon black, If it is normally used as a filler of rubber | gum, it can be used. Specific examples thereof include furnace black, acetylene black, thermal black, channel black, and graphite. Of these, furnace black is more preferable, and specific examples thereof include HAF-LS, HAF, HAF-HS, FEF, GPF, APF, SRF-LM, SRF-HM, and MT. Among these, MT carbon is more preferable.

Carbon black has the effect of reinforcing the crosslinked rubber. The content of carbon black is preferably 5 to 100 parts by mass, more preferably 10 to 50 parts by mass with respect to 100 parts by mass of the fluororubber. If the carbon black content is too small, the strength of the crosslinked product obtained by crosslinking may be low, and if it is too large, the elongation of the crosslinked rubber may be low. If it is within this range, the balance between strength and elongation is good.

Examples of other additives include fillers other than carbon black, processing aids, lubricants, lubricants, flame retardants, antistatic agents, colorants, fillers, and the like.
Examples of fillers other than carbon black include fluororesins such as polytetrafluoroethylene and ethylene / tetrafluoroethylene copolymers, glass fibers, carbon fibers, and white carbon. The content of the filler other than carbon black is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the fluororubber.
Examples of the processing aid include alkali metal salts of higher fatty acids, and stearates and laurates are preferred. The amount of the processing aid used is preferably 0.1 to 20 parts by mass, more preferably 0.2 to 10 parts by mass, and most preferably 1 to 5 parts by mass with respect to 100 parts by mass of the fluororubber.

As a method for producing the fluororubber composition used in the present invention, a fluororubber, a cross-linking agent, a cross-linking aid, and, if necessary, carbon black and other additives are kneaded with two rolls, a Banbury mixer, a kneader or the like. A method of kneading with the use of is preferred. Moreover, the method performed in the state melt | dissolved and disperse | distributed to the solvent is also employable.
The order of mixing the respective components is not particularly limited, but first, the components that are difficult to react or decompose due to heat generated during kneading are sufficiently kneaded with the fluororubber, and then easily reactable or easily decomposed. It is preferable to knead and mix an organic peroxide as a component. At the time of kneading, it is preferable to maintain the temperature at 120 ° C. or lower, which is a temperature at which the organic peroxide is hardly decomposed, by cooling with water.

In the present invention, at least one selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof acts as an adhesive between the metal substrate and the crosslinked fluororubber composition.
Any silane coupling agent may be used as long as it contains at least one polar functional group or reactive functional group in the molecular structure so as to be crosslinked and adhered to the fluororubber composition. Of these, amino group-containing silane coupling agents that have a stable structure even when the hydrolyzate is present in water are preferred. It is also preferable to use a combination of an amino group-containing silane coupling agent and another coupling agent.

The silane coupling agent is preferably at least one selected from the group consisting of an amino group-containing silane coupling agent, a vinyl group-containing silane coupling agent and a methacryloyloxy group-containing silane coupling agent. A mixture of a silane coupling agent containing a vinyl group and a silane coupling agent containing a vinyl group is more preferable.

Specific examples of the amino group-containing silane coupling agent include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-methyl- 3-aminopropyltrimethoxysilane, N-methyl-3-aminopropyltriethoxysilane, N-methyl-3-aminopropylmethyldiethoxysilane, N, N′-dimethyl-3-aminopropylmethyldimethoxysilane, N, N'-dimethyl-3-aminopropylmethyldiethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, etc. It is done. Among them, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxy Silane is preferred.

Examples of methacryloyloxy group-containing silane coupling agents include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Can be mentioned. Of these, 3-methacryloxypropyltrimethoxysilane is preferable.
Examples of the vinyl group-containing silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. Of these, vinyltrimethoxysilane and vinyltriethoxysilane are preferable.

The hydrolyzate of silane coupling agent and its partial condensate can be produced by dissolving silane coupling agent in an organic solvent such as alcohol and adding acidic water such as water or acetic acid water. After adjusting the amount of water to be added, in some cases, when heated, hydrolyzed and condensed, a stable silane coupling agent hydrolyzate and its partial condensate are produced with good storage stability. Can do.

In the present invention, at least one selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof acts as an adhesive, but the hydrolyzate of the silane coupling agent And a partial condensate thereof are preferable, and a mixture thereof is more preferable.

Hereinafter, at least one selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof is referred to as a silane coupling agent or the like. A silane coupling agent or the like is applied to the metal substrate as a solution.
The solvent used for the solution is not particularly limited. It is appropriately selected depending on working conditions. Examples of the solvent include methanol, ethanol, methyl ethyl ketone, acetone, ethyl acetate, methyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, butyl cellosolve, water, hexane and the like. Preferred are water-soluble solvents of methanol, ethanol, methyl ethyl ketone, methyl cellosolve, and ethyl cellosolve. As the solvent, only one kind of the above may be used, but it is preferable to use a mixture of two or more kinds in order to form a uniform adhesive layer.

Additives such as silicates, titanates, other coupling agents, and pigments may be mixed in the silane coupling agent solution as necessary.
Although the density | concentrations, such as a silane coupling agent of the said solution, are not specifically limited, 0.1-50 mass% is preferable, 1-40 mass% is more preferable, 5-30 mass% is the most preferable. Within this range, a uniform condensate coating film of silane tends to be formed, and the adhesive strength is good.

Specific examples of commercially available solutions containing the silane coupling agent include “MP-204” and “MP-205” manufactured by Yokohama Polymer Laboratory, “Chemlock 607” manufactured by Road Far East, “Chemlock Y4310-1”, “Chemlock AP-133”, and the like.
In the present invention, a solution containing the above silane coupling agent or the like is applied to the surface of a metal substrate by dipping, spin coating, spraying, brushing, roll coating, or the like, and then baked to form a surface of the metal substrate. An adhesive layer such as a silane coupling agent is formed thereon.

0-80 degreeC is preferable and, as for the temperature of a metal base material when a silane coupling agent etc. are apply | coated to a metal base material, 10-50 degreeC is more preferable. If the temperature of the metal exceeds 80 ° C, the solvent will easily evaporate immediately after the adhesive is applied, resulting in unevenness of the adhesive coating, and insufficient adhesive strength, leading to reduced adhesive strength. There is. If it is less than 0 degreeC, the water vapor | steam in the air may condense on the metal base-material surface. If moisture is condensed, a uniform coating cannot be formed, which leads to uneven adhesion.
The coating amount of the silane coupling agent is not particularly limited, but the dry film thickness obtained by coating is preferably 0.1 to 10 μm, more preferably 0.5 to 5 μm, and further preferably 1 to 3 μm. If the dry film thickness exceeds 10 μm, the adhesive strength may be reduced.

In this invention, after apply | coating solutions, such as a silane coupling agent, to a metal base material, it dries and bakes.
The drying temperature is usually preferably 40 ° C or lower, and more preferably 0 to 30 ° C. Drying at room temperature may be sufficient to air-dry, and it is preferable that water on the surface of the metal substrate can be removed. The drying time is not particularly limited and may be appropriately selected.
The baking temperature is 200 to 300 ° C, preferably 205 to 280 ° C, more preferably 210 to 270 ° C, and particularly preferably 210 to 260 ° C. By baking in this temperature range, excellent adhesion is maintained even after exposure to steam. The baking time is preferably 1 to 120 minutes, more preferably 5 to 60 minutes, and most preferably 10 to 30 minutes.

If the baking temperature and time are within the above ranges, a dehydration condensation reaction between silanol groups generated by hydrolysis of a silane coupling agent or the like occurs at a high rate, and a network by siloxane (Si-O-Si) bonds is generated. However, it is considered to form a strong skeleton that does not easily deteriorate even under harsh environments such as hot water and steam. Therefore, when such a strong adhesive layer is formed, peeling between the crosslinked fluororubber composition and the metal substrate is observed as a cohesive failure of the crosslinked fluororubber layer during the peeling test.

When the baking temperature is less than 200 ° C., the adhesive strength after exposure in a harsh environment such as steam is insufficient, and it is observed that the cross-linked fluororubber composition and the metal substrate peel off due to interfacial peeling. This is presumably because the dehydration condensation reaction between silanol groups does not occur sufficiently, and the adhesive layer does not become a strong skeleton.

The crosslinked fluororubber of the present invention peels the metal substrate and the crosslinked fluororubber after the pressure cooker test held in a steam atmosphere at 135 ° C. for 70 hours, and the ratio of cohesive failure of the fluororubber at the peeling interface is 80% or more. It is preferable that
Here, the ratio of cohesive failure refers to the area where the cross-linked fluororubber and the metal substrate at the peeling interface are not cohesive, but cohesive failure of the cross-linked fluororubber and the cross-linked fluororubber remains on the metal substrate ( This refers to the ratio of the area where no interfacial delamination between the cross-linked fluororubber and the metal substrate was observed to the total delamination area (the total of the interfacial debonding area and the cohesive failure area). ). Here, if the cohesive failure area ratio is 80% or more, it can be said that the adhesive strength is excellent.

  In the cross-linking adhesion method of the present invention, the cross-linkable fluororubber composition is placed on the surface of a metal substrate coated with a silane coupling agent and baked, and heated to cross-link and mold the fluororubber composition. A metal substrate and fluororubber are bonded. As a molding method, it is preferable to form and cross-link and bond by extrusion molding, injection molding, transfer molding, press molding or the like. In particular, pressure molding such as press molding is preferable because higher adhesive force can be obtained. The heating and pressing conditions are determined by the shape of the molded product, the decomposition temperature of the crosslinking agent to be used, and the like. Usually, about 120 to 200 ° C., 5 to 120 minutes, and about 0.5 to 20 MPa are preferable.

  In the cross-linked fluoro rubber obtained by bonding the metal base material of the present invention and the cross-linked fluoro rubber composition, the cross-linked fluoro rubber obtained by the above cross-linking adhesion (also referred to as primary cross-linking) may be supplied with electricity, hot air, steam or the like as a heat source. It is also preferable to further heat in an oven or the like to further promote crosslinking (also referred to as secondary crosslinking). The temperature during secondary crosslinking is preferably 150 to 280 ° C, more preferably 180 to 260 ° C, and most preferably 200 to 250 ° C. The secondary crosslinking time is preferably 1 to 48 hours, more preferably 4 to 24 hours. Sufficient secondary crosslinking is preferable because organic peroxide residues and the like contained in the crosslinked fluororubber are decomposed and volatilized and reduced, and the physical properties of the crosslinked fluororubber are stabilized.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, as a fluororubber composition used by the following examples and comparative examples, the following compounding agents and the compounding ratios shown in Table 1 were used.
(1) Fluororubber AFLAS 150P: Asahi Glass Co., Ltd., tetrafluoroethylene / propylene binary copolymer. Peroxide crosslinking type, fluorine content is 57% by mass. Hereinafter referred to as FEPM.
Daiel G-902: Daikin Co., Ltd., vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene terpolymer, peroxide crosslinking type, fluorine content is 71% by mass. Hereinafter referred to as FKM.
(2) Crosslinking aid TAIC: manufactured by Nippon Kasei Co., Ltd., triallyl isocyanate.

(3) Organic peroxide perbutyl P: manufactured by NOF Corporation, α, α′-bis (t-butylperoxy) -p-diisopropylbenzene.
Perhexa 25B: NOF Corporation, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (4) filler MT carbon: manufactured by CANCARB.
(5) Processing aid calcium stearate: manufactured by Kishida Chemical Co., Ltd.

Example 1
A metal test piece made of SUS316 having a thickness of 2.0 mm, a width of 25 mm, and a length of 60 mm was degreased with acetone and then washed with distilled water.
The washed metal test piece was dried with a dryer at 50 ° C. for 30 minutes and then left in a constant temperature room at 20 ° C. to adjust the metal test piece temperature to about 20 ° C.
Drying film thickness of cross-linking adhesive “MP-204” (amino group-containing silane coupling agent content: 1 to 5 mass%) manufactured by Yokohama Polymer Laboratory, which contains a silane coupling agent on the adhesive surface of the metal specimen Was applied once with a brush so as to be 1 μm and air-dried at room temperature for 10 minutes to remove moisture on the surface of the metal test piece. Subsequently, after baking for 15 minutes with a 250 degreeC dryer, it was air-cooled for 30 minutes at room temperature.

A metal test piece baked on a mold preheated to 170 ° C. is laid, and the FEPM composition shown in Table 1 is placed on the metal and press-crosslinked for 20 minutes at 170 ° C. under a pressure of 15 MPa. An adhesion test piece on which a FEPM layer was laminated was obtained.
The obtained adhesion test piece was subjected to "90 degree peeling test between rigid plate and crosslinked FEPM" according to JIS K6256, and the maximum peel strength and the cohesive failure area ratio on the surface of the metal substrate at the peeling interface were measured. It is shown in Table 2. Using a pressure cooker manufactured by Hirayama Seisakusho, after performing a steam resistance test under the conditions of a temperature of 135 ° C. and 70 hours, the above-mentioned peel test was performed again. The results are also shown in Table 2.

(Example 2)
An adhesion test piece was prepared in the same manner as in Example 1 except that the baking temperature was changed to 210 ° C. and the baking time was changed to 30 minutes. The results are shown in Table 2.
(Example 3)
An adhesion test piece was prepared in the same manner as in Example 1 except that the baking temperature was changed to 200 ° C. and the baking time was changed to 60 minutes. The results are shown in Table 2.
Example 4
The adhesive was changed to “Chemok 607” (content of amino group-containing silane coupling agent: 10 to 15% by mass) manufactured by Lord Far East, the baking temperature was changed to 200 ° C., and the baking time was changed to 60 minutes. An adhesion test piece was prepared in the same manner as in Example 1, and the test was performed in the same manner as in Example 1. The results are shown in Table 2.

(Example 5)
An adhesive test piece was prepared in the same manner as in Example 1 except that FEPM was changed to FKM and the baking time was changed to 30 minutes using the FKM composition shown in Table 1. The test was conducted. The results are shown in Table 2.
(Example 6)
As an adhesive, 99 g of methanol, 1 g of water, 1 g of ethylene glycol monoethyl ether (manufactured by Kanto Chemical Co., Inc.) and 10 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM903) are mixed and mixed at room temperature. By stirring for a time, the compounding adhesive 1 was obtained. In the compounding adhesive 1, the content rate of 3-aminopropyltrimethoxysilane was 9.0 mass%. An adhesive test piece was prepared in the same manner as in Example 1 except that the prepared adhesive 1 was used and the baking time was 10 minutes, and the test was performed in the same manner as in Example 1. The results are shown in Table 3.

(Example 7)
As an adhesive, 99 g of methanol, 1 g of water, 1 g of ethylene glycol monoethyl ether (manufactured by Kanto Chemical Co., Inc.), 10 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM903), vinyltrimethoxysilane (Shin-Etsu) 1 g of Chemical Co., Ltd .: KBM1003) was mixed and stirred at room temperature for 2 hours to obtain compounded adhesive 2. In compounded adhesive 2, the content ratio of 3-aminopropyltrimethoxysilane is 8.9% by mass, and the content ratio of 3-aminopropyltrimethoxysilane in the total silane coupling agent is 91% by mass. there were. An adhesive test piece was prepared in the same manner as in Example 1 except that the blended adhesive 2 was used and the baking time was 15 minutes, and the test was performed in the same manner as in Example 1. The results are shown in Table 3.

(Example 8)
As an adhesive, 99 g of methanol, 1 g of water, 1 g of ethylene glycol monoethyl ether (manufactured by Kanto Chemical Co., Inc.), 5 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM903), vinyltrimethoxysilane (Shin-Etsu) 5 g of Chemical Co., Ltd .: KBM1003) was mixed and stirred at room temperature for 2 hours to obtain compounded adhesive 3. In compounded adhesive 3, the content of 3-aminopropyltrimethoxysilane is 4.5% by mass, and the content of 3-aminopropyltrimethoxysilane in the total silane coupling agent is 50% by mass. there were. An adhesive test piece was prepared in the same manner as in Example 1 except that the blended adhesive 3 was used and the baking time was 15 minutes, and the test was performed in the same manner as in Example 1. The results are shown in Table 3.

(Comparative Example 1)
The test was performed in the same manner as in Example 1 except that baking was not performed. The results are shown in Table 4.
(Comparative Example 2)
The test was performed in the same manner as in Example 1 except that the baking time was changed to 150 ° C. and the baking time was changed to 30 minutes. The results are shown in Table 4.

(Comparative Example 3)
According to Patent Document 4, an amine curing agent (product name “diaminodiphenyl sulfone”, manufactured by Mitsui Toatsu Chemical Co., Ltd.) is used for cresol novolac type epoxy resin (epoxy equivalent: 218 g / eq) and 1 H for epoxy equivalent of 1 g / eq.
It was blended at a ratio of + g / eq, and dissolved in methyl ethyl ketone [MEK] so that the total mass of the epoxy resin and the amine curing agent was 3% to obtain an adhesive. The test was performed in the same manner as in Example 1 except that the adhesive was used, the baking temperature was 200 ° C., and the baking time was 5 minutes. The results are shown in Table 4.

(Comparative Example 4)
The test was performed in the same manner as in Comparative Example 3 except that the baking time was 60 minutes. The results are shown in Table 4.
(Comparative Example 5)
The test was performed in the same manner as in Example 5 except that the baking temperature was 190 ° C. The results are shown in Table 5.

(Comparative Example 6)
As an adhesive, “Metaloc S-10A” (content of amino group-containing silane coupling agent: 12 to 14% by mass) manufactured by Toyo Chemical Laboratory Co., Ltd. was used, the baking temperature was 120 ° C., and the baking time was 10 minutes. Except that, an adhesion test piece was prepared in the same manner as in Comparative Example 1, and the test was performed in the same manner as in Comparative Example 1. The results are shown in Table 5.

The cross-linked fluororubber obtained by the method of cross-linking adhesion between the fluororubber and the metal substrate of the present invention has an excellent metal base and cross-linked fluororubber composition even after exposure to steam, and has excellent steam resistance. Excellent in water resistance, water resistance, plasma resistance, heat resistance and chemical resistance. In particular, it is effective as a composite part such as an oil seal, particularly pipes, tubes, tanks, valves, engines, pumps, rolls, etc., used in fields requiring chemical resistance, steam resistance and heat resistance.

Claims (6)

When the fluororubber composition is crosslinked and bonded to the metal substrate, the metal substrate contains one or more selected from the group consisting of a silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof. A method of cross-linking and adhering fluororubber, which comprises applying the solution, drying, baking the substrate at a temperature of 200 to 300 ° C., and cross-linking the fluororubber composition. The method for cross-linking and bonding a fluororubber and a metal according to claim 1, wherein the cross-linking of the fluororubber composition is peroxide cross-linking using an organic peroxide. The method for crosslinking and bonding fluororubber according to claim 1 or 2, wherein the silane coupling agent is at least one selected from the group consisting of an amino group-containing silane coupling agent and a vinyl group-containing silane coupling agent. The cross-linking adhesion method of fluoro rubber according to any one of claims 1 to 3, wherein the cross-linking time of the fluoro rubber composition is 1 to 120 minutes. The temperature of the metal substrate when applying a solution containing at least one selected from the group consisting of the silane coupling agent, a hydrolyzate of the silane coupling agent, and a partial condensate thereof is 0 to 80 ° C. The method for cross-linking and adhering fluororubber according to claim 1. A cross-linked fluororubber obtained by the cross-linking adhesion method of fluororubber according to any one of claims 1 to 5, wherein the metal substrate and the cross-linked fluororubber after a pressure cooker test held in a steam atmosphere at 135 ° C for 70 hours The cross-linked fluororubber is characterized in that the ratio of cohesive failure of the cross-linked fluororubber composition at the peel interface is 80% or more.